Electrics are doing many wierd things.

During starting the engine power is cut to the headlamps and radio (normal behaviour). Intermittently this power is being cut at other times: either for long periods, or momentarily when switching between dip and main beam.

Sometimes the engine does not turn off when the ignition is turned off. On one occasion moving the headlamp dip switch stopped the engine.

Also intermittently when flash the headlamps the interior light flashed in sympathy and the joor locks jiggle (I am being serious, exactly this happens).

Latest happening is the central lockng has stopped working.

As far as I can tell the earths are good. They look clean, all lights are full brightness when they come on, and I cannot detect resistance or voltage drop.

No problems with startng, indicators or hazards if that is relevant.

Any ideas please?